[Elecraft] [K3] RE: K3: Relay noise?

[Joe Planisky]

Remember that some multi-layer ceramic capacitors can make noise  
("sing") due to piezoelectric effects.  Kemet has a short article (as  
a PDF document) explaining the phenomenon at

http://www.kemet.com/kemet/web/homepage/kfbk3.nsf/vaFeedbackFAQ/0EA15565AFC16E668525722500594468/$file/2006%2007%20ArrowAsiaTimes%20-%20MLC%20Noise.pdf

and a longer, more technical paper here:

http://www.kemet.com/kemet/web/homepage/kfbk3.nsf/vaFeedbackFAQ/118EBDDDFA5D532C852572BF0046B776/$file/2007%20CARTS%20-%20Reduced%20Microphonics%20and%20Sound%20Emissions.pdf


Or search for "singing capacitors" on your favorite search engine.

73
--
Joe KB8AP

On Dec 9, 2009, at 9:40 PM, AC7JW wrote:

>
> I could understand some sort of residual magnetic effect (for lack  
> of a better
> term) causing some mechanical movement to create the noise if it was  
> only
> present while running high power, in which case high currents are  
> present,
> and thus the potential for a powerful magnetic field. But at 1 watt-  
> there
> is something else going on.